Lux-an-open-source-physically-based-shading-framework

Hi Lars,

looked through your shaders to study and learn.. I had my own PBR already but for IBL I admit I preferred studying your source to reading paper after paper it seems like a simple technique behind the scenes but resulting in much improved visuals, real neat. I notice both DIFFCUBE_ON and SPECCUBE_ON use the cubemap.a to multiply with the cubemap.rgb. I'm wondering whether this is a common use-case and what's the need? I have typically dynamically rendered cubemaps so alpha will be 1 so I'm not particularly concerned, but I'm kind of wondering what the intended uses (and possible new effects) are with this in a "typical" IBL workflow.

(The other thing I'm wondering, but I'm soon gonna find out myself, is whether spec-IBL really adds much when one has diff-IBL, normal fresnel reflections and PBR-specular.. it already looks so freaking cool as-is but then I initially also doubted the usefulness of diff-IBL over complementary-sky+ground-ambient until I saw the results....)

So the simple question is, what's the point of a cubemap-alphachannel ...

 

hi metaleap,

multiplying rgb by a is what rgbm decoding looks like: if you use high dynamic range encoded cubemaps (they are stored in rgbm) the shader has to decode the final color.
if you have only ldr cubemaps you can simply skip it.
see: http://graphicrants.blogspot.de/2009/04/rgbm-color-encoding.html
for further details.

spec ibl is needed to simulate any kind of reflections. metal just won’t look like metal without it.

lars

 

Managed to get some time to test out new Quixel stuff and is very nice.
Decided to make a sci fi panel since they're quick and easy to make and with my limited time thats perfect.

Dont hate using a black render background lol xD I've already learnt not to use that but I couldnt be bothered making it grey for such an insignificant render

 

wow, quixel’s textures really make lux shine!

 

What the hell is Quixel thanks Lars for explaining, OK since RGBM isn't a RenderTextureFormat I guess I have to continue rendering my realtime cubemaps into ARGBHalf for HDR and can skip that multiply.

One thing I haven't really figured out from your code yet is whether spec-IBL replaces normal reflections, or replaces spec-CT/BP, or is added on top of both as just-another-additional-contribution.. will have to do some research. At some point near the end of LuxLightingAmbient you do this:

Code (csharp):

1.  
2. o.Emission = (1 - spec_ibl.rgb) * o.Emission + spec_ibl.rgb;
3.  

So this gets included in the surf frag-shaders before they are lit, and then as far as I know Unity's SS lighting model they do something like:

Code (csharp):

1. albedo * LightingLuxDirect_xyz() + o.Emission

or similar. OK so this looks as if, if one already has fresnel reflections in all shaders, then spec-IBL would replace those? Or blend both? I guess? Or maybe not... heck I'm lost now

 

@metaleap where da hell have you been? :O. They got 4 main programs, DDO is pretty much its a PBR texturing solution that is based around their dyna-mask, which allows amazing details to be created. NDO is a normal map creation tool. 3DO is a PBR rendering software integrated with photoshop and finally the standout I think of the bunch, Quixel Megascan. It provides a library of 8k, tileable, PBR ready textures.

 

hi metaleap,
spec ibl comes from ambient or indirect lighting and is added on top of the direct specular lighting (blinn phong or cook torrance).
fresnel is taken into account on both.

quixel: www.qixel.se

lars

 

THAT is Quixel.

 

Dude....!!!!!

 

Beat me to it! Glad they work as well as hoped, its good stuff

An alternative for texture sets that can cater for pbr is gametextures.com, its been a great mainstay and now i cant wait to chuck megascans in there as well

 

OK Quixel looks insanely cool once I progress from shader coding to creating/editing art, thanks for your patience folks

Lars, so if I understand this correctly this is basically like the bog-standard "cubemap-reflections with fresnel falloff", except you're using roughness for mip-level selection. This would explain why you don't have any specific "reflective" shaders in Lux, the need is served by "spec-IBL". Am I finally understanding this correctly?

 

Pretty much from what I understand

 

hahahaha

nice @Tiny Man you were able to get some time! really good results.

 

hi there,

i think you understand it correctly.
any (specular) shader is reflective. the sharpness and the amount of the reflection depends on roughness and specular color and can be controlled per texel.

lars

 

Got half a day break after my maths exam which was really easy (silly old mainstream)
Did more tiles thinking of ideas for my environment i'm gonna make, practicing with DDO and NDO etc.


In unity with lux and marmoset skyshop skyboxes.

I like this design for the tile so I might continue with it, make a tile set, some walls etc.

 

gotta move away from lux sadly ;(, cant use all the goodies new skyshop brings, so I made a simple pbr shader in shaderforge, stuff still looks good though except gloss seems slightly less spread out (i.e gloss has increased) all ok though.

 

I am getting some compile errors in LuxCubePorcessor.cs
after you call class :

Code (CSharp):

1. public class LuxCubeProcessor {
2.  
3.     public Cubemap cubeMap;
4.     public bool TakeNewProbe;
5.     public GameObject probe;
6.  
7.     public ConvoModes ConvolutionMode;
8.     public bool HighestMipIsReflection = true;
9.     public bool PullHDR;
10.  
11.     private Color[] CubeMapColors;
12.    
13.     public float SpecularPower = 2048; // Matches Lux SpecPower
14.  
15.  
16. #if UNITY_EDITOR

you have if unity editor check, but at the end of the file, you have the endif behind the closing } for the class.
When I fix that and put it in the } then other files fail to compile

 

hi vic,

i am not sure which version you refer to.
please make sure that you use the latest version from the github repository. that should work fine.

lars

 

This looks incredible! Never thought the robot scene could look this good!

 

Hi; Quixel users
I tried to download the (beta Quixel Suite) from the official website... but unforunately No way..
I hope somebody may push an advice how to get it...
Best regards

 

Here : https://d85clmw03d1co.cloudfront.net/suite/Install_Quixel_SUITE.zip

 

OK, I have a potentially stupid question.
I imported Lux from Github, which didn't have any environment maps included. So I'm trying to import one of my own. I've got an HDR file, which I tried importing into Photoshop and exporting an OpenEXR file which Unity can import, but when I try to turn it into a cubemap the colors go completely wrong.

Given a panoramic HDR file, how do I get this imported into Unity and working with Lux?

 

Thanks for trying to help...
in fact it was the same link I had tried several times and failed... here is the message I got
Unable to connect
Firefox can't establish a connection to the server at d85clmw03d1co.cloudfront.net.
Same problem with Opera OR Microsoft Internet explorer
I hope there would be another link
<<<<< EDIT >>>>>
OR; May be someone upload the zip file to any website, so I can download it...
It seems I'm requesting something in the wrong place...
sorry for bothering

 

hi there,
lux is not skyshop – so it does not allow you to convert panoramic pictures into cubemaps.
but lux allows you to capture and convolve hdr or ldr cubemaps or use any prepared one.

nevertheless i have updated the repo and added some base cubemaps to get you started.

lars

 

So, could I use Skyshop to convert the panorama, and then use that with Lux?

 

yes, you can.

 

Can someone point me at an article or something that can tell me what parameters I should input for concrete, wood, and brick? Basically for any surface. I grasp the basic concept and know how to work with metal but nothing else. What are you guys using for inputs? Will look at lots of sample scenes when I get a chance

 

Lux comes with the Dontnod Entertainment PBR chart, which should help.
There's also Quixel, which has a lot of built-in materials that you can sort of paint in the rough color inputs and then overlay your own images on top.

 

Good point.
Actually, i try to solve the problem with Substance Painter. Maybe someone with this same tool will be teaching us how to do..

 

I could. Make a megascan material chart wih all their new textures from the beta if you would like

 

Huh, I thought bout signing up for that. Will have to take a look

 

Hi there Lars,

I did some testing with Lux this evening, and when attempting to build to Android, the editor (v. 4.5) kept hanging on "Building Assets for Scene X" - this only happened when I had any shader from Lux set on a material that was being rendered in the scene. Do you know what might be going wrong?

I have the latest version of Lux off Github.

Thanks a bunch!

Edit - after some testing, this is happening on every platform I try and build to, and only when a Lux shader is present in the scene. This tells me it's a config problem somewhere... hopefully this helps nail it down a little.

 

hi there,

unfortunately i have to confirm this.
but i can only guess what is going wrong: on building a player all shaders get recompiled for the selected platform – even if i work on osx and built for osx.
it looks as if unity’s new shader compiler in 4.5 hangs up during this process due to the complexity of lux shaders.
commenting all #pragma multi_compile directives and replacing them with #define "solves" this issue…

so i think it is a bug in unity 4.5

lars

 

Are you both on 4.5.0 or 4.5.1? If you're sure this is reproducably a new shader-compilation bug in 4.5, you should definitely first submit it and then send @Aras the ticket ID

When building only for platform X, it certainly shouldn't compile all other platform versions on build.

 

Thanks for the reply Lars. That's a bummer - we should submit a bug report for sure.

Also, thanks for Lux. Truly stunning.

 

Good call. Will get on that.

 

i am using 4.5 – is 4.5.1 already out?

at least it should not crash! ;-)

 

Yes, 4.5.1 has been released.

 

I was wondering, I am using shader forge is there a way to add lux functionality to shader forge shaders?

 

Yeah. I just tested it today, I'm using 4.5.1 and It's also hanging on build.

I don't know much about shaders. I was wondering:
what does #define do different than #pragma multi_compile directive?

 

Ah , I see. I just noticed there was DIFFCUBE_On as default so I just changed it with DIFFCUBE_OFF and it did exactly that, ok I think I'm understanding the difference. So basically I have to specify instead of leaving all options.

Well, using #define is really simple and in the meantime it definitely solves the hanging problem when building with 4.5 and 4.5.1

 

not only that. it also reduces the size of the shader dramatically.
so using #define instead of #pragma multi_compile should always be your choice if it comes to preparing the built.

lars

 

That's perfect, I'll definitely keep using this in the future then.

Thanks lars

 

hey lars, is it possible to use lux in a shaderforge shader using skyshop IBL cubemaps? As I would love to have this combo.
If you could reply with an answer that would be great! Or at least lux working with shaderforge

 

hi there,
unfortunately lux is not supported by shader forge.
however tweaking the existing lux shaders is pretty simple as far as you have some expericnecs writing surface shaders.

lars

 

Ok lets see what my 0 surface shader experience can do , ill just muck around until it works

 

I have a question about the ease of use with the env probe cube script.

The guy in this video has a find close mesh button, is this already in the script or did i miss out on something? If it's not i think this would be great addition.

 

Hi all,

Just been checking out Lux - some really fantastic results even in the demo scene

We're thinking about using it for an architectural apartment demo. Has anyone tested the performance on a larger scale? How does it compare to regular materials?

Thanks,

Max

 

Here is an older post.

 

PBS of course is more expensive in the pixelshader. But it should absolutely be no problem on modern hardware – the number of drawcalls, post processing effects and other properties of your scene will most likely slow down rendering much more.
so if you pay attention to all common optimization opportunities like proper textures atlases, dynamic and static batching or even lod or occlusion culling lux should not have much impact on the rendering time.